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1. (WO2018181232) PRODUCTION METHOD FOR RESISTANCE SPOT WELDED JOINT

Pub. No.:    WO/2018/181232    International Application No.:    PCT/JP2018/012260
Publication Date: Fri Oct 05 01:59:59 CEST 2018 International Filing Date: Wed Mar 28 01:59:59 CEST 2018
IPC: B23K 11/20
B23K 11/11
B23K 11/18
B23K 11/30
Applicants: JFE STEEL CORPORATION
JFEスチール株式会社
Inventors: SAWANISHI Chikaumi
澤西 央海
MATSUDA Hiroshi
松田 広志
IKEDA Rinsei
池田 倫正
Title: PRODUCTION METHOD FOR RESISTANCE SPOT WELDED JOINT
Abstract:
Provided is a production method for a resistance spot welded joint that comprises a three-layer stack of two steel sheets and one aluminum sheet. The method makes it possible to produce a resistance spot welded joint that has favorable joint strength, regardless of the components and combination of steel sheets and aluminum sheets. The method involves stacking two steel sheets and one aluminum sheet such that one of the outermost sheets is a steel sheet and the other is the aluminum sheet and then joining the set of sheets by resistance spot welding. The method includes: a first electrification step that is for applying current to form, between the two steel sheets, a nugget that, when the sheet thickness of the thinner of the two steel sheets is tFe (mm), has a diameter of at least 2√tFe (mm); an electrification suspension step that is for suspending electrification after the first electrification step; and a second electrification step that is for applying current after the electrification suspension step.